/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.conf.directories;

import org.apache.iotdb.commons.cluster.NodeStatus;
import org.apache.iotdb.commons.conf.CommonDescriptor;
import org.apache.iotdb.commons.conf.IoTDBConstant;
import org.apache.iotdb.commons.utils.TestOnly;
import org.apache.iotdb.db.conf.IoTDBDescriptor;
import org.apache.iotdb.db.conf.directories.strategy.DirectoryStrategy;
import org.apache.iotdb.db.exception.DiskSpaceInsufficientException;
import org.apache.iotdb.db.exception.LoadConfigurationException;
import org.apache.iotdb.tsfile.fileSystem.FSFactoryProducer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * The main class of multiple directories. Used to allocate folders to data files.
 */
public class DirectoryManager {

    private static final Logger logger = LoggerFactory.getLogger(DirectoryManager.class);

    private List<String> sequenceFileFolders;
    private List<String> unsequenceFileFolders;
    private DirectoryStrategy sequenceStrategy;
    private DirectoryStrategy unsequenceStrategy;

    private DirectoryManager() {
        sequenceFileFolders =
                new ArrayList<>(Arrays.asList(IoTDBDescriptor.getInstance().getConfig().getDataDirs()));
        for (int i = 0; i < sequenceFileFolders.size(); i++) {
            sequenceFileFolders.set(
                    i, sequenceFileFolders.get(i) + File.separator + IoTDBConstant.SEQUENCE_FLODER_NAME);
        }
        mkDataDirs(sequenceFileFolders);

        unsequenceFileFolders =
                new ArrayList<>(Arrays.asList(IoTDBDescriptor.getInstance().getConfig().getDataDirs()));
        for (int i = 0; i < unsequenceFileFolders.size(); i++) {
            unsequenceFileFolders.set(
                    i, unsequenceFileFolders.get(i) + File.separator + IoTDBConstant.UNSEQUENCE_FLODER_NAME);
        }
        mkDataDirs(unsequenceFileFolders);

        String strategyName = "";
        try {
            strategyName = IoTDBDescriptor.getInstance().getConfig().getMultiDirStrategyClassName();
            Class<?> clazz = Class.forName(strategyName);
            sequenceStrategy = (DirectoryStrategy) clazz.newInstance();
            sequenceStrategy.setFolders(sequenceFileFolders);
            unsequenceStrategy = (DirectoryStrategy) clazz.newInstance();
            unsequenceStrategy.setFolders(unsequenceFileFolders);
        } catch (DiskSpaceInsufficientException e) {
            logger.error("All disks of folders are full.", e);
        } catch (Exception e) {
            logger.error("Can't find strategy {} for mult-directories.", strategyName, e);
        }
    }

    public void updateFileFolders() throws LoadConfigurationException {
        try {
            List<String> sequenceFileFolders =
                    new ArrayList<>(Arrays.asList(IoTDBDescriptor.getInstance().getConfig().getDataDirs()));
            for (int i = 0; i < sequenceFileFolders.size(); i++) {
                sequenceFileFolders.set(
                        i, sequenceFileFolders.get(i) + File.separator + IoTDBConstant.SEQUENCE_FLODER_NAME);
            }
            mkDataDirs(sequenceFileFolders);

            List<String> unsequenceFileFolders =
                    new ArrayList<>(Arrays.asList(IoTDBDescriptor.getInstance().getConfig().getDataDirs()));
            for (int i = 0; i < unsequenceFileFolders.size(); i++) {
                unsequenceFileFolders.set(
                        i,
                        unsequenceFileFolders.get(i) + File.separator + IoTDBConstant.UNSEQUENCE_FLODER_NAME);
            }
            mkDataDirs(unsequenceFileFolders);
            sequenceStrategy.setFolders(sequenceFileFolders);
            unsequenceStrategy.setFolders(unsequenceFileFolders);
            this.sequenceFileFolders = sequenceFileFolders;
            this.unsequenceFileFolders = unsequenceFileFolders;
            logger.info("Success to update file folders.");
        } catch (DiskSpaceInsufficientException e) {
            logger.error("Fail to update file folders, use previous folders.", e);
            throw new LoadConfigurationException(
                    "Fail to update file folders because all disks of folders are full, use previous folders.");
        }
    }

    public void updateDirectoryStrategy() throws LoadConfigurationException {
        String strategyName = "";
        try {
            strategyName = IoTDBDescriptor.getInstance().getConfig().getMultiDirStrategyClassName();
            Class<?> clazz = Class.forName(strategyName);
            sequenceStrategy = (DirectoryStrategy) clazz.newInstance();
            sequenceStrategy.setFolders(sequenceFileFolders);
            unsequenceStrategy = (DirectoryStrategy) clazz.newInstance();
            unsequenceStrategy.setFolders(unsequenceFileFolders);
            logger.info("Success to update directory strategy.");
        } catch (Exception e) {
            logger.error("Fail to update directory strategy {}, use previous strategy", strategyName, e);
            throw new LoadConfigurationException(
                    String.format(
                            "Fail to update directory strategy because can't find strategy %s for mult-directories, use previous strategy",
                            strategyName));
        }
    }

    public static DirectoryManager getInstance() {
        return DirectoriesHolder.INSTANCE;
    }

    private void mkDataDirs(List<String> folders) {
        for (String folder : folders) {
            File file = FSFactoryProducer.getFSFactory().getFile(folder);
            if (file.mkdirs()) {
                logger.info("folder {} doesn't exist, create it", file.getPath());
            } else {
                logger.info(
                        "create folder {} failed. Is the folder existed: {}", file.getPath(), file.exists());
            }
        }
    }

    public String getNextFolderForSequenceFile() throws DiskSpaceInsufficientException {
        try {
            return sequenceFileFolders.get(sequenceStrategy.nextFolderIndex());
        } catch (DiskSpaceInsufficientException e) {
            logger.error("All disks of wal folders are full, change system mode to read-only.", e);
            CommonDescriptor.getInstance().getConfig().setNodeStatus(NodeStatus.ReadOnly);
            throw e;
        }
    }

    public List<String> getAllSequenceFileFolders() {
        return new ArrayList<>(sequenceFileFolders);
    }

    public String getNextFolderForUnSequenceFile() throws DiskSpaceInsufficientException {
        try {
            return unsequenceFileFolders.get(unsequenceStrategy.nextFolderIndex());
        } catch (DiskSpaceInsufficientException e) {
            logger.error("All disks of wal folders are full, change system mode to read-only.", e);
            CommonDescriptor.getInstance().getConfig().setNodeStatus(NodeStatus.ReadOnly);
            throw e;
        }
    }

    public List<String> getAllUnSequenceFileFolders() {
        return new ArrayList<>(unsequenceFileFolders);
    }

    public List<String> getAllFilesFolders() {
        List<String> folders = new ArrayList<>(sequenceFileFolders);
        folders.addAll(unsequenceFileFolders);
        return folders;
    }

    @TestOnly
    public void resetFolders() {
        sequenceFileFolders =
                new ArrayList<>(Arrays.asList(IoTDBDescriptor.getInstance().getConfig().getDataDirs()));
        for (int i = 0; i < sequenceFileFolders.size(); i++) {
            sequenceFileFolders.set(
                    i, sequenceFileFolders.get(i) + File.separator + IoTDBConstant.SEQUENCE_FLODER_NAME);
        }
        unsequenceFileFolders =
                new ArrayList<>(Arrays.asList(IoTDBDescriptor.getInstance().getConfig().getDataDirs()));
        for (int i = 0; i < unsequenceFileFolders.size(); i++) {
            unsequenceFileFolders.set(
                    i, unsequenceFileFolders.get(i) + File.separator + IoTDBConstant.UNSEQUENCE_FLODER_NAME);
        }
    }

    private static class DirectoriesHolder {
        private static final DirectoryManager INSTANCE = new DirectoryManager();
    }
}
